Shape memory hydrogels (SMHs) are functional polymer materials with the advantages of shape memory effect

high water content

and good biocompatibility. Their porous structures and high strength provide excellent tissuelike microenvironments for cell adhesion

growth and migration. Particularly

the shape memory abilities under external stimuli endow them attractive applications in artificial intelligence and medicines. The progress in synthetic methods

principle of shape memory as well as their applications including 3D printing

sensors

soft robots

tissue engineering

and information transmission are reviewed in this paper. Based on structures and properties

challenges and research trends faced by SMHs are discussed.